Chili lime aioli:
Combine all the ingredients in a bowl, or for a smoother consistency place in blender and blend until smooth and well combined. Set aside.
In a sauce pan (wide enough to fit brats) add about 1 tablespoon of vegetable oil on low to medium heat. Add peppers and onions and sauté 5-8 minutes. Then add beer, chicken broth, cumin, brown sugar, pinch of salt and pepper. Bring to a low simmer and add brats. Let brats simmer in mixture 15-20 min. Then turn off heat and let them rest.
Take onion and cilantro and finely chop and place in bowl to set aside for later. Heat a pan on medium heat and butter the hot dog buns and put in pan until toasted and remove. In the same pan add a little vegetable oil and remove brats from peppers and beer and sauté or until nice and browned on a grill. Take some peppers and onions, put on bun, with browned brats, and top with Chile lime aioli and cilantro and onions.